Expenditure for rehabilitation following knee arthroplasty for osteoarthritis- and rehabilitation-related challenges following discharge to home after surgery is not available in the Indian context. To estimate cost of rehabilitation and document challenges in following rehabilitation advices, from a patient perspective. We conducted a hospital-based cross-sectional study of patients visiting the orthopedic department at a tertiary care public-funded hospital in New Delhi and included those who recently (less than 4months) underwent primary knee arthroplasty for osteoarthritis. A trained physiotherapist not involved in clinical care collected information on expenditures incurred after discharge from hospital, patient's ability to recall the advices given by the physician and challenges they experienced using a semi-structured questionnaire. We report median costs by category of direct and indirect cost and used linear regression to explore determinants of cost. We interviewed 82 consecutive patients (mean age 60.8years and 68% females) with median time since surgery of 28days. More than half (52%) sought some support for physiotherapy. The median cost of rehabilitation was INR 18,395 (Interquartile-range 11,325-27,775). Direct medical cost contributed to 74% of total cost (32% fee for services, 21% medications and lab investigations, 21% assistive devices). Twenty percent higher costs were incurred among those undergoing bilateral knee surgery after adjusting for age, sex, income, and type of physiotherapy support sought. Challenges were related to recall of advices, not understanding the recovery process and pain management. About half patients undergoing knee arthroplasty seek support for rehabilitation after discharge to home contributing to a major portion of expenses incurred during rehabilitation. Cost-effective support mechanism for home-based rehabilitation is required for improving patient rehabilitation experiences. The online version contains supplementary material available at 10.1007/s43465-021-00405-6.